body {
  width: 640px;
  margin: 0 auto;
}
.wrong {
  background-color: darkslategray;
  color: whitesmoke;
}
.failed {
  background-color: darkslateblue;
  color: azure;
}

.higher {
  background-color: indianred;
  color: darkred;
}

.lower {
  background-color: lightgreen;
  color: seagreen;
}